Test runs to improve Shinkansen speeds started on June 25, 1962. On that date in 2014, a plaque to mark the birthplace of the Shinkansen was unveiled to the media at the Kamonomiya maintenance station. Satoshi Kubo, who worked as assistant stationmaster for the prototype line, looked back at the days of the test runs.
The prototype line was built two years before the scheduled start of Shinkansen services. Kubo was in charge of collecting data from test runs and sending it to JNR designers.
He described air pressure variations in the tunnel as a "troubling thing" toward the very end. When trains rushed into the tunnel at high speed, the pressure inside the car changed considerably, causing ear pain and rendering interior doors inoperable.
"Before the test runs, we collected data when the prototypes ran over level ground without any tunnels. Nobody knew what would happen inside a tunnel."
After conducting various tests, including those in which trains passed each other in the tunnel, JNR hastily changed the design for Shinkansen cars to make them airtight.
It was hard work for JNR to conduct tests and revamp designs at the same time. But Kubo said, "We, all 450,000 employees, were united to work on it." He showed a photo of executives such as President Shinji Sogo and chief engineer Hideo Shima with workers at the prototype line. "The top executives of a gigantic company with 450,000 employees were photographed with workers who only finished middle school and those with marginal positions," Kubo recalled. "Top executives took trial rides and got firsthand experience at construction sites. It was great for us to have such an open atmosphere."